World of Warcraft launched in the US on Nov 23rd 2004 and Feb 11th 2005. Blizzard have said that anyone who opened their account within 60 days of these dates (and is presumably still playing now) will be getting something special in the post. How far off were you from getting this exclusive reward?
I was 2 days off... (account opened on the 15th of April 2005)
If you want to check when your account was opened. Go to battle.net, log in, click your WoW tab, account history and scroll all the way to the bottom. The bottom most date will be when you started your account (should be a free month).